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Author
Watson, Dan M.
Calvet, Nuria P.
Fischer, William J.
Forrest, W. J.
Manoj, P.
Megeath, S. Thomas

Melnick, Gary J.
Najita, Joan
Neufeld, David A.

Sheehan, Patrick D.

Stutz, Amelia M.

Tobin, John

Affiliation
Univ Arizona, Steward ObservIssue Date
2016-08-29Keywords
Herbig-Haro objectsISM: jets and outflows
shock waves
stars: jets
stars: pre-main sequence stars: protostars
Metadata
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IOP PUBLISHING LTDCitation
EVOLUTION OF MASS OUTFLOW IN PROTOSTARS 2016, 828 (1):52 The Astrophysical JournalJournal
The Astrophysical JournalRights
© 2016. The American Astronomical Society. All rights reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
We have surveyed 84 Class 0, Class I, and flat-spectrum protostars in mid-infrared [Si II], [Fe II], and [S I] line emission, and 11 of these in far-infrared [O I] emission. We use the results to derive their mass. outflow rates, (M) over dot(w). Thereby we observe a strong correlation of (M) over dot(w) with bolometric luminosity, and with the inferred mass accretion rates of the central objects, (M) over dot(a), which continues through the Class 0 range the trend observed in Class II young stellar objects. Along this trend from large to small mass. flow rates, the different classes of young stellar objects lie in the sequence Class 0-Class I/flat-spectrum-Class II, indicating that the trend is an evolutionary sequence in which (M) over dot(a) and (M) over dot(w) decrease together with increasing age, while maintaining rough proportionality. The survey results include two that. are key tests of magnetocentrifugal outflow-acceleration mechanisms: the distribution of the outflow/accretion branching ratio b = (M) over dot(w)/(M) over dot(a), and limits on the distribution of outflow speeds. Neither rules out any of the three leading outflow-acceleration, angular-momentum-ejection mechanisms, but they provide some evidence that disk winds and accretion-powered stellar winds (APSWs) operate in many protostars. An upper edge observed in the branching-ratio distribution is consistent with the upper bound of b = 0.6 found in models of APSWs, and a large fraction (31%) of the sample have a. branching ratio sufficiently small that only disk winds, launched on scales as large as several au, have been demonstrated to account for them.ISSN
1538-4357Version
Final published versionSponsors
NASA [NNX14AF79G]Additional Links
http://stacks.iop.org/0004-637X/828/i=1/a=52?key=crossref.7c1a5b468d289a57fabc1ad65cf7782dae974a485f413a2113503eed53cd6c53
10.3847/0004-637X/828/1/52